1. Field of the Invention
The present invention relates to an intake system of an engine. More particularly, the invention pertains to a structure including an intake module in which a throttle body joint portion and an upstream portion of an intake manifold are formed in a single structure and a downstream portion of the intake manifold that is connected to the intake module.
2. Description of the Related Art
Various intake system designs for an engine have been proposed in recent years, in which an intake system including an intake manifold or part of an intake manifold is formed of synthetic resin material. When using the synthetic resin material in the intake system, it is essential to design the system in such a way that it has adequate stiffness for supporting the intake manifold and its associated parts.
An example of a conventional support mechanism for an intake system is proposed in Japanese Unexamined Patent Publication No. 09-189272. According to the Publication, an upper manifold made of synthetic resin is located above one bank of a V-type engine with a branch portion of the upper manifold at its one end connected to a lower manifold so that the branch portion at one end of the upper manifold is supported by an engine body in a manner that the branch portion of the upper manifold can freely move vertically, while the other end of the upper manifold is rigidly joined to the engine body via a support rod, for example.
In the conventional support mechanism of this kind, it is necessary to provide dedicated members for ensuring supporting stiffness like the support rod mentioned above in addition to members constituting the intake system. Thus, the conventional support mechanism for the intake system is associated with a problem that the support mechanism has an intricate construction which could result in an increase in manufacturing cost.
In light of the foregoing, it is an object of the invention to provide an intake system of an engine, wherein a throttle body joint portion and an upstream portion of an intake manifold are combined to form a one-piece intake module which is connected to a downstream portion of the intake manifold, the intake module being constructed such that it can be formed of synthetic resin material or the like, and wherein the intake system has increased mechanical stiffness to support the intake module while employing a simplified support mechanism.
According to the invention, an intake system of an engine comprises an intake module in which a throttle body joint portion and an upstream portion of an intake manifold are formed in a single structure and a downstream portion of the intake manifold, the downstream portion extending from an engine body and being connected to a downstream end of the intake module, the engine including an oil filler pipe of which lower end is connected to the engine body and upper end is connected to the intake module such that the intake module is supported by the engine body via the oil filler pipe.
In this construction, the intake module is connected to the intake manifold and is supported by the engine body via the oil filler pipe, so that sufficient mechanical stiffness for supporting the intake module is obtained. In particular, because the intake module is supported by using the oil filler pipe, mechanism for supporting the intake module is simplified.
In the intake system thus constructed, it is preferable that the lower end of the oil filler pipe be connected to an oil pan provided in the engine body and an oil catch chamber connected to the upper end of the oil filler pipe be integrally formed in the intake module.
This construction is advantageous in that the number of components is reduced resulting in a cost reduction compared to conventional structures in which an oil catch chamber is formed separately from an intake module.
These and other objects, features and advantages of the invention will become more apparent upon reading the following detailed description in conjunction with the accompanying drawings.